Air return bulkhead

ABSTRACT

An air return bulkhead is disclosed which may be adapted to fit on differently-sized trailer walls around differently-sized trailer refrigeration units. The bulkhead includes an upper support panel with ridges or other discontinuities thereon. The discontinuities bound areas sized to accommodate standard refrigeration units, and a cutting tool may be easily guided along these discontinuities to form a space wherein the refrigerator may be fit when the bulkhead is mounted to the trailer wall. Also disclosed is a bulkhead which includes flutes and columns thereon wherein the ends of the flutes and columns may be removed by use of a cutting tool to allow the bulkhead installer to tailor the airflow into the refrigerator inlet as desired.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority under 35 USC §120 to U.S. patentapplication Ser. No. 08/607,229 filed Feb. 26, 1996, the entirety ofwhich is incorporated by reference herein.

FIELD OF THE INVENTION

[0002] The present invention relates generally to air return bulkheadsfor trailers for insuring proper flow of refrigerated air therein, andmore specifically to universal-mount air return bulkheads which may berapidly modified to fit on different trailer walls withdifferently-sized makes and models of refrigeration units thereon.

DESCRIPTION OF THE PRIOR ART

[0003] Refrigerated trailers are commonly used to transport perishablecargo on roadways in order to distribute the cargo to consumers in afresh condition. These refrigerated trailers are specially designed foreffective cooling of the cargo. The refrigeration unit for the traileris generally mounted on the front wall of the trailer with a portionprotruding into the interior of the trailer. The refrigerator inlet islocated on the lower portion of the refrigerator adjacent the trailerinterior front wall, and the refrigerator outlet is located on the topportion of the refrigerator near the trailer ceiling. As a result,warmer air is pulled from the trailer front wall, cooled, and blownalong the ceiling of the trailer toward the trailer rear wall. The cargois stacked on the trailer floor so that it is spaced from the trailerceiling and the walls of the trailer. The floor of the trailer may be afalse floor with a space located beneath, or as illustrated by thedrawings in U.S. Pat. No. 2,923,384 to Black, the trailer floor maycomprise a-series of rails, ridges, or similar raised structures withlengths oriented from the front of the trailer to the rear of thetrailer. In either case, the floor supports the cargo but allowsrefrigerated air to flow rearward along the trailer ceiling, along thetrailer rear wall, and beneath the cargo and toward the front of thetrailer. The refrigerator inlet then pulls the air in so that it may berecooled and again ejected rearwardly along the trailer ceiling. Thiscooling methodology allows a steady recirculating flow of refrigeratedair to surround the entirety of the cargo, thereby keeping it at a coldtemperature.

[0004] However, it has been found that cargo can sometimes shift duringtransport and slide against the front or rear wall of the trailer toblock the circulating air. To prevent this problem, a bulkhead includinga series of ribs or ridges thereon is frequently mounted to the frontwall below the refrigerator inlet. This bulkhead, which is often calleda “lattice-type” air return bulkhead, preserves the passage of air tothe refrigerator inlet along the front wall even if cargo shifts againstit. The spacing between the ridges is such that cargo cannot fittherein, thereby preventing shifting cargo from moving between or behindthe ridges and obstructing the circulation of air. The lattice-type airreturn bulkhead may even extend over the refrigerator and toward thetrailer ceiling to protect the refrigerator from damage from shiftingcargo. One lattice-style air return bulkhead sold by Donovan Enterprises(LaGrange, Georgia) includes a series of vertically-oriented beamsmounted to the trailer front wall below and adjacent to therefrigerator. A number of spaced horizontally-oriented slats are mountedto the beams to form a web-like slat framework spaced from the frontwall of the trailer. Air can thereby flow from the floor between thebeams and into the refrigerator inlet. The slats prevent cargo fromshifting between the beams and blocking air flow. A similarlattice-style air return bulkhead is sold by Aero Industries(Indianapolis, Ind.).

[0005] However, when some types of lattice-style bulkheads are used,there is a possibility that cargo adjacent the refrigerator can shift sothat spaces between the cargo provide an air passage between the bottomand top of the refrigerator. Air exiting the refrigerator outlet nearthe ceiling of the trailer can then be pulled directly downward towardthe front wall of the trailer, through the lattice of the bulkhead, andback into the refrigerator inlet, rather than circulating through thetrailer by flowing along the trailer ceiling towards the trailer's rearwall. This phenomenon, known as “short cycling,” sends freshly cooledair into the refrigerator inlet and causes the thermostat in therefrigerator inlet to misread the air temperature in the trailer. Therefrigerator then shuts down prematurely, resulting in product thawingand unsafe temperatures for foodstuffs.

[0006] To reduce the problem of short cycling, much of the truckingindustry has been switching to “solid-style” or “false wall” air returnbulkheads, which provide a solid, continuous wall spaced a shortdistance from the front wall of the trailer and surrounding therefrigerator inlet. The false wall air return bulkhead is opened nearthe floor of the trailer to allow air to flow from the trailer floor,behind the bulkhead wall, and into the refrigerator inlet. Because thefalse wall air return bulkhead provides a barrier between therefrigerator inlet and outlet and an effective refrigerator inlet nearthe trailer floor, the air exiting from the refrigerator cannot re-enterthe refrigerator inlet unless it circulates throughout the trailerfirst. As a result, the false wall air return bulkheads work quite wellin preventing short cycling. A summary of prior art false wall airreturn bulkheads follows.

[0007] U.S. Pat. No. 3,206,946 to Lindersmith et al. illustrates a falsewall air return bulkhead which includes two parallel panels connected inspaced relation by a number of support beams. One panel (the “wallpanel”) is attached to the trailer front wall so that the other panel(the “floating panel”) is maintained in spaced relation from the trailerfront wall. Warm air from the floor passes between the panels to reachthe refrigerator inlet. A series of vertically oriented, generallysinusoidal indentations or flutes are included in the floating panel toenhance heat transfer from the air passing between the panels to the airin the remainder of the trailer.

[0008] U.S. Pat. No. 5,427,237 to Kiefer et al. discloses a shippingcrate for a refrigeration unit which may be converted to a false wallair return bulkhead. The resulting bulkhead utilizes side rib memberswhich fit vertically on the trailer front wall on either side of therefrigerator, and central rib members which are placed at a diagonal onthe trailer front wall beneath the refrigerator inlet. A planar floatingpanel is then attached to these rib members so that it is supported inspaced relation to the trailer front wall and so that it covers thelower portion of the refrigerator and the refrigerator inlet, therebyisolating the refrigerator inlet from the refrigerator outlet. Palletstops in the form of C-shaped bumpers are then placed beneath the panelbetween the panel and the floor. These pallet stops prevent pallets orother cargo from shifting forward during transport, moving under thepanel, and blocking air flow to the refrigerator inlet. The pallet stopsalso prevent pallets or other cargo from sliding beneath the panel andpossibly catching and damaging the panel when the cargo is later liftedout of the trailer for removal.

[0009] U.S. Pat. No. 4,399,737 to Severson illustrates a false wall airreturn bulkhead having a floating panel spaced from the trailer frontwall. Side support panels descend from the sides of the floating paneland extend into abutment with the trailer front wall near the trailerside walls. Corrugations or flutes are depressed into the floating panelbetween the panel and the trailer front wall. The top of the floatingpanel is placed in abutment with the refrigerator adjacent therefrigerator inlet. Supplementary panels or extension members are thenattached to the top of the floating panel on both sides of therefrigerator to isolate the refrigerator inlet and prevent air exitingthe refrigerator outlet from reentering the inlet. These supplementarypanels may include apertures at their sides to allow air adjacent theside walls of the trailer to flow inward towards the refrigerator inlet.The bulkhead is made in several different heights, and the supplementarypanels can have several different widths. This allows the bulkhead to befitted onto differently-sized trailer front walls arounddifferently-sized refrigerators. The bulkhead components are generallyconstructed of KEVLAR-reinforced fiberglass/plastic composite.

[0010] The AERGUARD air return bulkhead (Aero Industries, Indianapolis,Ind.), includes a number of Z-shaped beams which are vertically mountedon the trailer front wall below the refrigerator inlet and near thetrailer side walls. Elongated top and bottom floating panels are thenmounted horizontally across the tops and bottoms of the beams to leave acentral aperture between the beams. A fiberglass reinforced plywoodcenter floating panel is then bolted to the beams between the top andbottom panels to close the central aperture. Bumpers or pallet stops areplaced between the bottom of the beams and the floor. Supplementarypanels are then placed on top of the top panel on both sides of therefrigerator to complete a barrier between the refrigerator inlet andoutlet. A mesh screen may be fit around the inlet portion of thebulkhead, i.e. between the lower panel and the trailer floor and trailerfront wall, to prevent debris from entering the refrigerator. A varietyof differently-sized bulkheads are sold to allow the bulkheads to beused with differently-sized refrigerators.

[0011] An air return bulkhead sold by Donovan Enterprises (LaGrange,Georgia) is somewhat similar to the AERGUARD air return bulkhead notedabove. Metal beams are vertically mounted on the trailer front wall nearthe trailer side walls. A fiberglass reinforced floating panel ismounted to these beams in spaced relation to the front wall.Supplementary panels are then mounted to the top of the floating panelon both sides of the refrigerator to complete a barrier between therefrigerator inlet and outlet.

[0012] The prior art also illustrates a “hybrid” air return bulkheadwhich incorporates features of both lattice and false wall bulkheads.The AIRHEAD air return bulkhead (Air Flo Products, Madison, Wis.) is alattice-style bulkhead integrally formed of high density polyethylene.The READ bulkhead essentially consists of a planar wall panel with aseries of raised parallel columns thereon. The wall panel is mounted tothe trailer front wall beneath a refrigerator so that the columns areoriented vertically, thereby allowing air to flow between the columnsfrom the trailer floor to the refrigerator inlet. The ends of thecolumns include apertures so that air can also flow within the columnsthemselves. Thus, the columns are arranged in a lattice formation, buteach column in itself forms a floating wall. The columns arehorizontally spaced to such an extent that cargo cannot shift to blockair flow between the columns.

[0013] However, the prior art air return bulkheads generally tend tohave one or more of the following disadvantages.

[0014] First, owing to their web-like, largely open structure, thelattice-style prior art air return bulkheads allow air to flow directlyagainst cargo in abutment with the bulkhead, thereby more fully coolingthis cargo. However, as noted above, the lattice-style prior artbulkheads can also allow refrigerated air to pass directly from therefrigerator outlet to the refrigerator inlet, resulting in shortcycling. False wall air return bulkheads largely prevent short cycling,but at the same time they do not allow refrigerated air to flow directlyagainst cargo adjacent the false wall. As a result, false wall bulkheadsmay not cool cargo adjacent the bulkhead as efficiently as lattice-stylebulkheads. The art is in need of an air return bulkhead which allowsefficient cooling of cargo adjacent the bulkhead, but which prevents theoccurrence of short cycling at the same time.

[0015] Second, the prior art air return bulkheads are time-consuming toassemble and install. Assembly time represents lost trailer use andeconomic loss, and for that reason, the art has long been seekingbulkheads which may be rapidly and easily assembled, as well asdisassembled and replaced. This long-felt need for an air returnbulkhead with lesser installation time is evidenced, for example, by thesales literature for the prior art bulkheads noted above. Such salesliterature inevitably touts the installation time of the particularbulkhead to which it pertains. Thus far, a one-hour installation timefor a bulkhead has been viewed favorably by trailer owners.

[0016] Third, most of the prior art air return bulkheads are not welladapted for convenient display by retailers. Because the prior artbulkheads are somewhat large, retailers generally do not have sufficientspace to stock all of the varieties of bulkheads needed to fit all ofthe different varieties of trailers and refrigerators. At the same time,owing to the wide variety in trailer and refrigerator sizes, it isnecessary that the retailer carry a large number of differently-sizedbulkheads in order to ensure that a properly fitting bulkhead will be onhand when a trailer owner asks for it. If a properly sized bulkhead isnot available, the trailer owner must generally wait two or three weeksfor a properly sized bulkhead to be delivered. If the trailer cannot beused in the meantime, this can represent a significant economic loss tothe trailer owner.

[0017] Fourth, the prior art air return bulkheads are not designed forpoint-of-sale display in such a manner that they are appealing toconsumers. Because most prior art bulkheads are made of a collection ofseparate panels, beams, and similar components, they generally appear toconsumers as no more than an agglomeration of parts in need of assembly.The appearance and fit of the prior art bulkheads generally cannot bevisualized by trailer owners until the bulkheads have actually beeninstalled on the front wall of the trailer. In contrast, a bulkheadwhich uses fewer parts, or a bulkhead which could be presented tocustomers in substantially assembled form, would be more appealing toconsumers.

[0018] Fifth, the prior art air return bulkheads are subject to bendingand/or cracking or splintering due to the impact of shifting cargo, anddue to temperature changes within the trailer. These events can producesharp edges on the bulkheads which can catch and damage cargo, or injurepeople working within the trailer.

[0019] Sixth, the prior art air return bulkheads, which include airinlets only along their bottom edges, are highly susceptible toclogging. It is a common phenomenon for plastic cargo wrappings, e.g.,shrink wrap, to tear during loading or transport and fall off of cargo.The plastic wrap is then blown along the trailer floor and sucked acrossor into the inlets, thereby crippling the refrigerator's air intake andpreventing air circulation.

[0020] Finally, the prior art is also in need of an air return bulkheadwhich is resistant to damage and collapse from shifting cargo loads;which is lightweight to reduce fuel consumption; which is resistant torust, mildew and rot, ultraviolet radiation, and/or swelling from waterabsorption; which can be manufactured of materials approved by theUnited States Department of Agriculture and the United States Food andDrug Administration for contact with foodstuffs; which does not catch oncargo and thereby cause damage to the cargo (or the bulkhead) when thecargo is being removed from the trailer, which has low friction so thatcargo rubbing against it or lifted against it will not be damaged; whichis inexpensively manufactured and attractive in appearance; and which isrecyclable.

SUMMARY OF THE INVENTION

[0021] The present invention involves an air return bulkhead whichsolves the aforementioned disadvantages and which meets theaforementioned objectives. The invention is directed to an air returnbulkhead for attachment to a wall having a refrigerator mounted thereon.The bulkhead includes a floating panel having a front face and anopposing rear face bounded by an edge. The edge includes an upper edgeportion located at the top of the floating panel and having a sizegreater than the width of the refrigerator. An upper support panelextends across the entirety of the upper edge portion and descends fromthe upper edge portion to conclude at a terminal edge. The bulkhead alsoincludes attachment means for mounting the bulkhead to the wall with theterminal edge of the upper support panel in abutment with the wall.After the bulkhead is mounted to the wall, a portion of the uppersupport panel may be cut away to define a space wherein the refrigeratormay be fit.

[0022] Unlike the air return bulkheads of the prior art, the bulkheadincludes an upper support panel descending from the upper edge portionand extending across the entirety of its length. This support panel mayinclude cut guiding means thereon for guiding a cutting tool, e.g., asmall valley wherein a cutting blade may fit, or a ridge against which acutting blade may be guided. The cut guiding means define apredetermined path which bounds areas sized to accommodate standardprior art refrigerators. Installers can snugly fit the bulkhead on anytrailer wall, about any refrigerator, by merely trimming the supportpanel along the cut guiding means. A space is thereby formed in thesupport panel wherein the refrigerator can fit so that the support paneland floating panel isolate the refrigerator inlet from the refrigeratoroutlet. In contrast, prior art bulkheads do not include such acontinuous support panel, and instead merely include an apertureadjacent the upper edge portion wherein the refrigerator is fit. Toisolate the refrigerator inlet from the refrigerator outlet, thisaperture must be closed by supplementary panels or extension members. Tofit these prior art bulkheads on different walls about differentrefrigerators, multiple differently-sized bulkheads need to bemanufactured with differently-sized supplementary panels, and theseparts require substantial assembly by the bulkhead installer. No priorart references, alone or in combination, teach or suggest the inclusionof the aforementioned support panel or the reduction in manufacturingcosts and installation time that it provides.

[0023] The air return bulkhead of the present invention is preferablyintegrally formed of a thin material, most preferably plastic, and itmay include other structural features as well. Some of these structuralfeatures are as follows.

[0024] First, the bulkhead may include a lower edge portion at thebottom of the floating panel, and a support column may rest below thislower edge portion. The support column may include opposing column endswith column walls extending therebetween. Cut guiding means may beincluded on the support column for guiding cutting tools, wherein thecut guiding means bound an area which may be removed to define anaperture on the support column. The installer can thereby easily add oneor more apertures to the support column so that the support column wallsdefine a passage which opens upon the front and rear of the bulkhead,and so that the airflow pattern provided by the bulkhead may be modifiedas desired. Additional cut guiding means can be added to the supportcolumns to allow them to be cut to a desired length. Multiple supportcolumns may be provided, and their respective heights may be differentto obtain desired airflow properties. Web members connecting one columnwall on one support column to one column wall on another support columnmay also be provided.

[0025] Second, the bulkhead may include a support flute depressedinwardly from the front face of the floating panel, wherein the supportflute includes opposing flute ends with flute walls extendingtherebetween. The support flute may further include cut guiding meansfor guiding cutting tools, wherein the cut guiding means bound an areawhich may be removed to define an aperture on the support flute. Byremoving these areas, the installer can add one or more apertures to thesupport flute so that the support flute walls define a passage whichopens upon the front and rear of the bulkhead, and so that the airflowpattern provided by the bulkhead may be modified as desired. Additionalcut guiding means can be added to the support flute so that it can becut to a desired length. The flute ends may be formed integrally orseparately from the column ends, and the flute walls may be formedintegrally or separately from the column walls. Multiple support flutesmay be provided, and their respective heights may be different to obtaindesired airflow properties.

[0026] Third, a side support panel may descend from either or each sideedge portion of the floating panel between the upper and lower edgeportions. A side webs can then extend from each side support panel torest on the sides of the floating panel in a plane which is generallyparallel to the floating panel. Each side web may include a web supportcolumn protruding therefrom, the web support column including opposingweb column ends with web column walls extending therebetween. Cutguiding means for guiding cutting tools may be included on the websupport column, wherein the cut guiding means bound an area which may beremoved to define an aperture on the web support column. The installercan thereby add one or more apertures to the web support column so thatthe web column walls define a passage which opens upon the front andrear of the bulkhead, and so that the airflow pattern provided by thebulkhead may be modified as desired. Multiple web support columns may beprovided, and their respective heights may be different to obtaindesired airflow properties. Cut guiding means for guiding cutting toolsmay further be provided between the side webs and the remainder of thebulkhead so that the bulkhead installer may sever the side webs from thebulkhead if desired, or cut guiding means may be provided on the websupport columns to allow them to be cut to a desired length.

[0027] Preferably, all surfaces resting between the floating panel andthe terminal edge of the support panel, e.g., the support panel, thecolumn walls, and the flute walls, are oriented at an angle of no lessthan approximately 5° (as measured from the perpendicular to the frontface) so that multiple bulkheads may be stacked in interlocking fashionfor efficient storage and display.

[0028] The invention is also directed to an air return bulkheadcomprising a floating panel having a front face and an opposing rearface bounded by an edge. The edge includes a lower edge portion and asurrounding edge portion. At least one support panel extends from thesurrounding edge portion and terminates in a terminal edge, which may beplaced in abutment with a wall to maintain the floating panel in spacedrelation to the wall. At least one support flute is depressed inwardlyfrom the front face of the floating panel, and the support fluteincludes flute walls extending generally between the plane of the frontface and a parallel plane which includes the terminal edge.Alternatively or additionally, at least one support column is includedbelow the lower edge portion. The support column includes column wallsextending generally between the plane of the front face and a parallelplane which includes the terminal edge. The bulkhead may include one ormore of the structural features noted above, such as the side webs, sidesupport columns, and cut guiding means located on various areas of thebulkhead.

[0029] The invention is also directed to a method of fitting an airreturn bulkhead on a wall around a refrigerator. First, an air returnbulkhead is provided. The bulkhead includes a floating panel having afront face and a rear face bounded by an edge, wherein the edge includesan upper edge portion greater in size than the refrigerator. A supportpanel extends from the upper edge and terminates in a terminal edge. Thesupport panel is formed of thin material capable of being cut byhand-held cutting means. Second, a portion of the support panel is cutaway to form a space sized to accommodate the refrigerator. The terminaledge of the bulkhead is placed in abutment with the wall, with therefrigerator resting within the space. The bulkhead is attached to thewall by use of attachment means.

[0030] The method may further include any one or more of the followingsteps: providing support columns extending from the edge of the floatingpanel, and cutting apertures in the support columns to modify thebulkhead's airflow characteristics or cutting the support columns to adesired length; providing support flutes depressed within the floatingpanel, and cutting apertures in the support flutes to modify thebulkhead's airflow characteristics; and/or cutting away other portionsof the bulkhead, e.g., the floating panel, to allow the bulkhead to fitabout the refrigerator or other objects mounted on from the wall, or tomodify the bulkhead's airflow characteristics.

[0031] To summarize, the air return bulkhead of the present inventiondecreases manufacturing costs because a single bulkhead is capable offitting any size of trailer and refrigerator. Segments of the bulkheadmay be cut away by the use of commonly available hand-held cutting toolsto rapidly adapt the bulkhead to differently sized trailers and/orrefrigerators. As a result, the bulkhead may be modified to fit thetrailer and refrigerator in question and installed within fifteenminutes. The bulkhead allows air to flow against cargo resting adjacentthe bulkhead, but at the same time it prevents short-cycling andblockage of the air flow between the floor and the refrigerator inlet.The bulkhead prevents shifting cargo from damaging the trailer frontwall and/or refrigerator. It does not include any horizontal slats orrungs which can catch cargo being lifted from the trailer, and it hasless sharp edges to puncture or otherwise damage cargo or injurepersonnel working within the trailer. The bulkhead is not as susceptibleto bending, cracking, or splintering as the bulkheads of the prior art.The support columns, support flutes, and floating panel of the bulkheadinclude angled surfaces to allow multiple bulkheads to be stacked ininterfitting relation for easy storage and display, thereby allowingsellers to carry a greater number of them in stock with minimal storagespace. Additionally, the bulkhead has low weight (approximately 47 lbsor 21 kg), and it may be easily lifted and held against the front wallof the trailer to visualize its appearance and performance. Since thebulkhead is preferably made of plastic, e.g., high molecular weightpolyethylene, it is also recyclable; it is not subject to rusting orswelling from water absorption; it can be made resistant to mold,mildew, and ultraviolet radiation; it can be formed of materials whichare approved by government agencies for contact with foodstuffs; and ithas low friction when raising or lowering cargo against it.

[0032] Further features and advantages of the invention will bediscussed in the Detailed Description of the Invention following theBrief Description of the Drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0033]FIG. 1 is a front perspective view of the bulkhead of the presentinvention.

[0034]FIG. 2 is a rear perspective view of the bulkhead of FIG. 1.

[0035]FIG. 3 is a sectional view of the bulkhead of FIG. 1 along thelines 3-3 of FIG.

[0036]FIG. 4 is a sectional view of the bulkhead of FIG. 1 along theline 44.

[0037]FIG. 5 is a perspective view of the bulkhead of FIG. 1 shownmounted on a front trailer wall.

[0038]FIG. 6 is a front perspective view of an alternate embodiment ofthe bulkhead of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0039] Referring to the Figures of the drawings, in which the same orsimilar features are designated by the same reference numeralsthroughout, a first embodiment of the air return bulkhead is shown inFIGS. 1 and 2 at the reference numeral 10. The bulkhead 10 is preferablyintegrally formed of plastic, most preferably high molecular weightpolyethylene, though it may be formed of composite materials, e.g.,fiberglass, or metal, e.g., aluminum. The bulkhead materials may bechosen for resistance to mildew and ultraviolet radiation, and for safecontact with foodstuffs. When it is formed of plastic, the bulkhead 10is preferably formed by thermoforming methods known to the art, e.g., byvacuum forming or plug and ring forming.

[0040] The bulkhead 10 includes a generally planar floating panel 12having a front face 14 and a rear face 16 which are bounded by a paneledge 18. The panel edge 18 may be considered to include a lower edgeportion 20 and a surrounding edge portion 22, which in itself may beconsidered to include two side edge portions 24 and an upper edgeportion 26. The bulkhead 10 further includes a generally planar wallpanel 28 which is located within a plane generally parallel to andspaced from the floating panel 12. A series of support panels 30 connectthe wall panel 28 and the floating panel 12, and these descend from thepanel edge 18 of the floating panel 12 to conclude at a terminal edge 32common to the wall panel 28. The wall panel 28 extends from the terminaledge 32 of the support panels 30 to terminate in a lower edge 34, twoside edges 36, and two upper edges 38 on opposing sides of the floatingpanel 12. As illustrated in FIG. 5, this bulkhead 10 structure allowsthe wall panel 28 to be affixed to a front wall 300 of a trailer 302 sothat the terminal edge 32 of the support panels 30 abuts the trailerfront wall 300, and so that the floating panel 12 is spaced from thetrailer front wall 300. The floating panel 12, support panels 30, andthe trailer front wall 300 thereby define a plenum chamber (not shown inthe Figures) between the floating panel 12 and the trailer front wall300.

[0041] The support panels 30 include an upper support panel 40descending from the upper edge portion 26 of the panel edge 18, a lowersupport panel 42 descending from the lower edge portion 20 of the paneledge 18, and two side support panels 44, each descending from the sideedge portions 24 of the panel edge 18. A series of apertures 46 may belocated in the lower support panel 42, thereby allowing air to pass fromthe area in front of and below the floating panel 12 to the plenumchamber between the floating panel 12 and the trailer front wall 300.Alternatively, the lower support panel 42 may be eliminated entirely toprovide apertures 46 between the floating panel 12 and wall panel 28 andadjacent the lower edge portion 20 of the panel edge 18.

[0042] As will be discussed shortly, cargo is intended to be stackedagainst the floating panel 12 after the wall panel 28 of the bulkhead 10has been attached to a wall. To ensure that the floating panel 12 willremain spaced from the wall when cargo shifts against it, the floatingpanel 12 preferably includes one or more support flutes 48 depressedinwardly from its front face 14. Each support flute 48 includes opposingflute walls 50, a flute floor 52, a first flute end 54 adjacent thelower edge portion 20, and a second flute end 56 located within thefloating panel 12. As illustrated best by FIG. 1, the first flute ends54 may be integral with the lower support panel 42. The flute walls 50and flute ends 54 and 56 extend between the plane of the floating panel12 and the plane of the wall panel 28 so that the flute floor 52 restsgenerally within the same plane as the wall panel 28. The flute walls 50thereby help to maintain the floating panel 12 in spaced relation fromthe wall. The support flutes 48 are spaced from each other so that theyeffectively form a series of slots in the front face 14 of the floatingpanel 12, as seen in FIG. 1, and are sized so that cargo of standardsizes cannot shift between them.

[0043] To further strengthen the floating panel 12, the flute walls 50may include support ridges 58. Each support ridge 58 has a generallysemicylindrical shape, and each is aligned with an axis orientedgenerally perpendicular to the floating panel 12 and wall panel 28, orwith its axis at a generally acute angle to a perpendicular to thefloating panel 12 and/or wall panel 28. The support ridges 58 enhancethe rigidity of the flute walls 50 and better enable the floating panel12 to resist damage from cargo shifting.

[0044] In order to prevent cargo from sliding beneath the lower supportpanel 42 and blocking the air flow through the apertures 46 into theplenum chamber, the bulkhead 10 may include one or more support columns60 descending from the lower support panel 42 and the lower edge portion20 of the floating panel 12, and protruding from the wall panel 28.Throughout this specification, the term “support column” is to beunderstood as describing columns located beneath the effective inlet tothe plenum chamber, i.e., beneath the apertures 46, and thus this termdoes not encompass the structure of the floating panel 12 locatedbetween adjacent support flutes 48. The support columns 60 arepreferably shaped similarly to the support flutes 48, and includeopposing column walls 62, a column floor 64, a first column end 66adjacent the lower edge 34 of the wall panel 28, and a second column end68. As illustrated best by FIG. 1, the second column ends 68 may beintegral with the lower support panel 42 and/or the first flute ends 54of the support flutes 48. Where multiple support columns 60 are used,they are preferably spaced so that cargo of standard sizes cannot shiftbetween adjacent columns 60 during cargo shifting. The column walls 62may include support ridges 70 similar to the support ridges 58 toenhance the rigidity of the support columns 60. The wall panel 28effectively forms a series of web members 72 which connect a column wall62 of one support column 60 to a column wall 62 on an adjacent supportcolumn 60.

[0045] The wall panel 28 of the bulkhead 10 can further be considered toinclude side webs 74 which each extend generally from the terminal edges32 of the side support panels 44 to the side edges 36 of the wall panel28. These side webs 74 may each include one or more web support columns76, each of which is preferably similar in form to the support columns60. The web support columns 76 may each include two opposing web columnwalls 78, a web column floor 80, and opposing web column first ends 82and web column second ends 84. As with the support columns 60, the webcolumn walls 78 may extend between the plane of the floating panel 12and the plane of the wall panel 28 so that the web column floor 80 islocated generally within the same plane as the floating panel 12. Theweb support columns 76 may also include support ridges 86.

[0046] A flange 88 may be provided at the top of the bulkhead 10 so thatit protrudes from an upper edge 90 of the upper support panel 40 (i.e.,the terminal edge 32 of the upper support panel 40) and the upper edges38 of the wall panel 28, and so that it rests within generally the sameplane as the wall panel 28. The flange 88 may be riveted or otherwiseattached to the trailer front wall 300 at various portions along itslength to insure that the upper edge 90 of the upper support panel 40 isin tight abutment with the trailer front wall 300, thereby decreasingthe possibility of air leakage from in front of the bulkhead 10 to theplenum chamber behind the bulkhead 10.

[0047] As previously noted, one of the primary deficiencies of the priorart bulkheads is that they are not easily adapted to fit differenttrailer walls and refrigeration units. In order to fit differently-sizedwalls and refrigerators, the prior art bulkheads utilizedifferently-sized floating panels in accompaniment withdifferently-sized supplementary panels or extension members which fit ontop of the floating panel to surround the refrigerator. The bulkhead 10avoids the need for manufacturing and assembling differently-sizedfloating panels and supplementary panels by providing a cut guidingmeans on the upper support panel 40 for guiding cutting tools along apredefined path which bounds discrete areas wherein different prior artrefrigerators may be fit. Thus, by guiding a cutting tool alongdifferent cut guiding means on the upper support panel 40, the installermay cut differently-sized apertures in the upper support panel 40 whichaccommodate differently-sized refrigerators.

[0048] As illustrated in FIG. 1, the cut guiding means is preferably inthe form of a series of cutting ridges 92 on the upper support panel 40.These cutting ridges 92 comprise a raised lip on the front of thebulkhead 10 (i.e., a depressed valley on the rear of the bulkhead 10)having a height of approximately {fraction (1/8)} inch (0.3 cm). Becausethese cutting ridges 92 provide a discontinuity in the otherwise smoothand planar surface of the upper support panel 40, they present a clearlydefined path along which a cutting tool may be guided. The cuttingridges 92 include a lower cutting ridge 94 at the upper edge portion 26(i.e., near the boundary of the upper support panel 40 and the floatingpanel 12), and an upper cutting ridge 96 at the upper edge 90 of theupper support panel 40. Vertically oriented cutting ridges are thenprovided at equally-spaced distances from the central vertical axis ofthe bulkhead 10: two first vertical cutting ridges 98, which arepreferably spaced 37 inches (94 cm) apart (i.e., each at 18.5 inches/47cm from the central vertical axis of the bulkhead 10); and two secondvertical cutting ridges 100, which are preferably spaced 66 inches (168cm) apart (i.e., each at 33 inches/84 cm from the central vertical axisof the bulkhead 10). The area on the upper support panel 40 bounded bythe first vertical cutting ridges 98 and the lower and upper cuttingridges 94 and 96 therebetween defines a first cutaway segment 102 whichmay be easily and rapidly cut out by use of hand cutting tools to fitstandard 37 inch refrigerator units. Similarly, the area on the uppersupport panel 40 bounded by the second vertical cutting ridges 100 andthe lower and upper cutting ridges 94 and 96 therebetween defines asecond cutaway segment 104 which can be cut away with hand-held cuttingtools to allow the bulkhead 10 to fit around standard 66 inchrefrigerator units. As seen in FIG. 5, after the proper cutaway segmentis removed, the bulkhead 10 may be fit on the trailer front wall 300beneath the refrigerator 304. The lower edge of the refrigerator 304fits into the aperture in the bulkhead 10 formed by the removal of thecutaway segment so that the upper support panel 40 surrounds a lowerportion of the sides of the refrigerator 304. By fitting the bulkhead 10on the trailer front wall 300 in this manner, the refrigerator inletrests within the plenum chamber, and the inlet is thereby effectively“moved” to the apertures 46 in the lower support panel 42.

[0049] It is understood that the cut guiding means may be formed byraised lips, depressed valleys, or any other forms of discontinuities inthe surface of the bulkhead 10 which would allow one to guide a cuttingtool along the surface of the bulkhead 10. It is further understood thatthe cut guiding means is not strictly necessary for the use and practiceof the bulkhead 10. The bulkhead 10 could be provided without the cutguiding means, and the installer could simply cut the bulkhead 10 at theappropriate places in order to allow it to be installed on the trailerfront wall 300 around the refrigerator 304. However, it has been foundthat the cut guiding means is beneficial in that it eliminates the needfor measuring standard refrigerator dimensions and properly placing andmarking them on the bulkhead 10, and it also provides a sure guide for acutting tool and reduces the chances of an inaccurate cut. An accuratecut enhances the fit of the bulkhead 10 around the refrigerator 304 andreduces the possibility of air leakage from the front of the bulkhead 10to the plenum chamber behind the bulkhead 10.

[0050] It is also understood that the cut guiding means could be addedto other portions of the bulkhead 10 if desired. For example, thecutting ridges 92 could extend into the floating panel 12 so thatportions of the floating panel 12 may easily be removed to allow thefloating panel 12 to surround the lower edge of the refrigerator 304 anda lower portion of its sides, and so that the bulkhead 10 can be mountedhigher on the trailer front wall 300. Additionally, cutting ridges couldbe added to separate the side webs 74 from the remainder of the wallpanel 28 so that an installer could entirely remove the side webs 74 andthe web support columns 76 if desired. Cutting ridges 106 may also beprovided at the upper edges 38 of the wall panel 28 to allow the flange88 to be removed if the installer so desires. A cutting ridge could beprovided along the upper edge 90 of the upper support panel 40 betweenthe upper support panel 40 and the flange 88, but this is not necessarybecause the angled interface between the flange 88 and the upper supportpanel 40 provides a discontinuity in the contour of the bulkhead 92along which a cutting tool may be guided. Cutting ridges could also beadded at various points along the lengths of the support flutes 48 andsupport columns 60 so that portions of their lengths may be removed toadjust their sizes.

[0051] The bulkhead 10 is also adapted to allow an installer to tailorthe air flow provided by the bulkhead 10 as desired. As best shown byFIG. 1, this is done by providing terminal raised portions 108 at any orall of the first and second flute ends 54 and 56 of the support flutes48, the first column ends 68 of the support columns 60, and the firstand second ends 82 and 84 of the web support columns 76. The boundariesof the raised portions 108 form a cut guiding means for guiding for acutting tool so that the raised portions 108 may be easily removed wheredesired. An installer could, for example, cut away the raised portions108 at the first flute ends 54 and second flute ends 56 of the supportflutes 48, and at the first column ends 66 of the support columns 60, sothat air will flow from the trailer floor 306 through the supportcolumns 60 and support flutes 48. When cargo is stacked against thefloating panel 12, the air flowing through the support flutes 48 willdirectly contact the cargo and thereby cool it to a greater extent. Theair will then enter the apertures formed by the removal of the raisedportions 108 at the second flute ends 56 so that the air may enter theplenum chamber and return to the refrigerator inlet. Similarly, theraised portions 108 at the web column first and second ends 82 and 84may be removed from the web support columns 76 to allow a greatereffective air flow passage at the sides of the floating panel 12. Any orall of the raised portions 108 at the first and second flute ends 54 and56 of the support flutes 48, the first column ends 66 of the supportcolumns 60, and the web column first and second ends 82 and 84 of theweb support columns 76 may be removed to allow the installer to tailorthe airflow as desired.

[0052] The removal of the raised portions 108 at any of theaforementioned locations has the additional advantage that such removalforms additional air inlets for the refrigerator which are located awayfrom the apertures 46. This makes it less likely that plastic wrap orother debris can simultaneously clog all of the air inlets.

[0053] As FIG. 1 illustrates, a lip 110 may be provided about theperimeter of the wall panel 28 at its lower and side edges 34 and 36.The lip provides a discontinuity in the contour of the wall panel 28against which rivets or other fasteners can be placed duringinstallation of the bulkhead 10. This prevents sliding or displacementof the fasteners during attachment of the bulkhead 10 to the trailerfront wall 300, and thereby enhances the speed of installation.

[0054] Preferably, all surfaces of the bulkhead 10 located between thefloating panel 12 and the wall panel 28, e.g., the support panels 30,the flute walls 50 and ends 54 and 56, and the column walls 62 and ends66 and 68, are at an angle so that multiple bulkheads 10 can be easilystacked atop each other in interfitting relation for easy storage. Oncestacked, the floating panels 12, support panels 30, support flutes 48,support columns 60, etc. are adjacently situated in parallel relation.An angle of 10° has been found to work well in allowing multiplebulkheads to be stacked and unstacked, and preferably the surfaces areoriented at no less than 5°. However, the upper support panel 40 ispreferably aligned at a 45° angle for easier cutting of the cuttingridges 92 when the wall panel 28 of the bulkhead 10 is placed on theground during installation.

[0055] Where multiple support flutes 48 are used, the support flutes 48may include two outer support flutes 112 and one or more central orinnermost support flutes 114 resting therebetween. As illustrated inFIGS. 1 and 2, the support flutes 48 may be staggered in height so thatthe support flutes 48 located more centrally within the floating panel12 are shorter, i.e., so that the support flutes 48 grow shorter fromthe outer support flutes 112 to the central support flutes 114. Thisensures that the suction pressure exerted by the refrigerator inlet onthe second flute end 56 of each support flute 48 will be approximatelyequal, thereby creating approximately equal airflow within each supportflute 48 and preventing decreased cooling near the center or sides ofthe trailer 302.

[0056] Certain dimensions are preferred for the bulkhead 10. The widthof the bulkhead, i.e., the width of the lower edge 34, is preferablyapproximately 86 inches (218 cm) long. The overall height of thebulkhead 10, i.e., the height of the side edges 36, is preferablyapproximately 70 inches (178 cm). The width of the floating panel 12,i.e., the width of the upper and lower edge portions 20 and 26, ispreferably approximately 70 inches (178 cm), providing a width ofapproximately 8 inches (20 cm) for each of the web members 72. The websupport columns 76 are preferably approximately 60.5 inches (154 cm)long. The support columns 60 are preferably approximately 16 inches (41cm) long and the support flutes 48 preferably vary in height from amaximum of 28.5 inches (72 cm) for the outer support flutes 112 to aminimum of 20.5 inches (52 cm) for the innermost support flutes 114. Thebulkhead 10 preferably has an overall thickness of approximately 4.5inches (11 cm), i.e., the floating panel 12, column floor 64, and webcolumn floor 80 are spaced approximately 4.5 inches from the plane ofthe wall panel 28 so that the refrigerator intake of standardrefrigerators will fit behind the plane of the floating panel 12. Theoverall thickness of the bulkhead material is preferably approximately0.225 inches (0.6 cm). The top flange 88 is preferably 1 inch (2.5 cm)wide.

[0057] The installation and operation of the bulkhead 10 can bedescribed as follows. The installer may take the bulkhead 10 and removethe first cutaway segment 102 or second cutaway segment 104 (or adifferently sized segment) so that the remaining portion of the uppersupport panel 40 will properly fit around the refrigerator 304 as shownin FIG. 5. As noted above, the removal of these segments can be done byuse of a hand-held cutting tool, e.g., a battery-powered portable drillhaving a rotary cutting wheel attachment, at the cutting ridges 92.Because the bulkhead 10 only weighs approximately 47 pounds (21 kg), itis easily maneuvered and manipulated by a single person for cutting andmounting on the trailer front wall 300. The user may additionally severthe side webs 72 from the bulkhead 10 if desired, or may cut into thefloating panel 12 to extend the first or second cutaway segments 102 and104 so that a portion of the floating panel 12 will surround therefrigerator 304 and so that the bulkhead 10 will fit higher up on thetrailer front wall 300. Portions of the flange 88 may be cut away asdesired. The flange 88, and the wall panel 28 at its web members 72and/or side webs 74, may then be riveted to the trailer front wall 300or attached by other attachment means known to the art, e.g., by use offasteners or brackets, adhesives, or welding. The refrigerator inlet isthereby enclosed behind the bulkhead 10 within the plenum chamber, andan effective refrigerator inlet is formed at the apertures 46. Thebulkhead 10 can be cut and attached to a trailer front wall 300 inapproximately 15 minutes, approximately one quarter of the time requiredfor most prior art bulkheads. It can be appreciated that themanufacturer of the bulkhead 10 does not need to manufacturedifferently-sized floating panels, supplementary panels, or extensionmembers to properly fit the bulkhead 10 around the refrigerator 304, andthe installer of the bulkhead 10 does not need to assemble multipleparts in order to form a working bulkhead. Because the bulkhead 10 is auniversal mounts bulkhead, both the manufacturer and installer can savemoney by reducing manufacturing, assembly, and installation time.

[0058] The installer may cut away other portions of the bulkhead 10either before or after installation to obtain the desired air flowcharacteristics for the bulkhead. For example, the raised portions 108at the first and second flute ends 54 and 56 of the support flutes 48and the first column ends 66 of the support columns 60 may be cut awayto provide an effective refrigerator inlet at the first column ends 66.Air circulation is increased because it may flow through the firstcolumn ends 66 as well as the apertures 46. Additionally, air flowingthrough the support flutes 48 will flow directly against cargo restsagainst the floating panel 12. The raised portions 108 at the first andsecond ends 82 and 84 of the web support columns 76 may also be removedto further increase air circulation. It is understood that an installercould remove any or all of the raised portions 108 on the ends of thesupport flutes 48, support columns 60, and web support columns 76 toobtain any desired air flow pattern.

[0059] It is important to note that numerous features described abovefor the bulkhead 10 are not required to use the bulkhead 10 and obtainits benefits. For example, the side support panels 44 and side webs 74may be omitted entirely if the floating panel 12 and upper support panel40 are to span the entire width of the trailer front wall 300 betweenthe trailer side walls 308. The installer need only cut the uppersupport panel 40 to accommodate the refrigerator 304, and then installthe bulkhead 10 on the trailer front wall 300 so that the upper supportpanel 40 and floating panel 12 isolate the refrigerator inlet from therefrigerator outlet and form an effective refrigerator inlet nearer thetrailer floor 306. Support flutes 48 and support columns 60 may then beused to strengthen the bulkhead 10, and the flute ends 54 and 56 andfirst column ends 66 may be cut to allow the airflow about the bulkhead10 to be modified as desired.

[0060] Other modifications and additions to the bulkhead 10 arecontemplated and considered to be within the spirit of the invention. Alist of exemplary modifications and additions follows. This list is notintended to be exhaustive, but is rather intended to merely illustratesome of the possible alternative embodiments of the bulkhead 10contemplated by the inventor.

[0061] First, the bulkhead 10 may be used in combination with plugsformed of plastic or other material which are sized to removably fitwithin the apertures formed by the removal of the raised portions 108 atthe first and second flute ends 54 and 56 of the support flutes 48, thefirst column ends 66 of the support columns 60, and the first and secondends 82 and 84 of the web support columns 76. Such plugs allow theinstaller to remove all of the raised portions 108 to form apertures,and then permanently or temporarily plug some or all of the apertures tochange the air flow within the trailer 302 as the installer desires.Therefore, if a cargo owner specifies that a certain air flow pattern isrequired, the installer can use the plugs to retroactively modify theair flow pattern. As an example, where the raised portions 108 at thesecond flute ends 56 of the support flutes 48 and the first column ends66 of the support columns 60 are cut away, an effective refrigeratorinlet is formed at the first column ends 66 when cargo rests against thefloating panel 12. However, when no cargo rests against the floatingpanel 12 to channel air from the first flute end 54 to the second fluteend 56, the effective refrigerator inlet is moved to the second fluteend 56. If the installer does not want this to occur, a plug can beinstalled into the second flute end 56 when the cargo content of thetrailer 302 decreases to the point where the second flute end 56 isexposed.

[0062] Second, the support flutes 48, the support columns 60, and theweb support columns 76 may have a curved form rather than the linearform illustrated in the Figures.

[0063] Third, support ridges such as the support ridges 58, supportridges 70, and support ridges 86 may be included on the upper supportpanel 40, lower support panel 42, and side support panels 44 as well ason other portions of the bulkhead 10.

[0064] Fourth, the raised portions 108 at the first and second fluteends 54 and 56 of the support flutes 48, the first column ends 66 of thesupport columns 60, and the first and second ends 82 and 84 of the websupport columns 76 need not literally be raised, and can take the formof areas bounded by cut guiding means such as the cutting ridges 92noted above. Similarly, the apertures 46 need not be provided in thebulkhead 10 and can instead be defined by cut guiding means on the lowersupport panel 42 so that the installer can form the apertures 46.

[0065]FIG. 6 illustrates another embodiment of the bulkhead of thepresent invention at the reference number 200. As with the bulkhead 10,the bulkhead 200 has a floating panel 202 with support flutes 204integrally formed therein, and a wall panel 206 with support columns 208and web support columns 210 formed therein and integrally joined to thefloating panel 202. The web support columns 210 are included on side webportions 212 of the wall panel 206, and cutting ridges 214 are includedto allow the installer to separate the side web portions from theremainder of the wall panel 206 by use of a cutting tool if desired. Thefloating panel 202 extends further upward than the side web portions212, and it does not include cutting ridges thereon, requiring aninstaller to measure and mark cut lines by hand. To further enhance theresistance of the floating panel 202 to stresses imposed by cargoshifting, the floating panel 202 includes a support post 216 formedtherein. The term “support post” is used to define any area depressedinto the plane of the wall panel 206 and located away from the edges ofthe floating panel 202. The support post 216 includes a support postfloor 218 which rests generally within the plane of the wall panel 206,and support post walls 220 extending between the floating panel 202 andthe support post floor 218. The bulkhead 200 may be installed andoperated in generally the same fashion as the bulkhead 10, but thesupport post floor 218 provides an additional area which may be attachedto the trailer front wall 300. It is understood that multiple supportposts 216 could be included within the floating panel 202, just as anynumber of support flutes 204, support columns 208, and web supportcolumns 210 may be used.

[0066] It is understood that the various embodiments of the bulkheadsdiscussed above can also be mounted on walls and placed in use withoutcutting them beforehand. As an example, it may be possible to provide arefrigerator for a trailer which is flush with the front wall of thetrailer. In that case, the bulkheads described above may be mounted onthe front wall of the trailer so that the upper support panel restsbetween the refrigerator inlet and outlet to isolate them from eachother. No cutting is necessary to fit the bulkhead around therefrigerator.

[0067] It is understood that the invention is not confined to theparticular construction of parts and uses described and illustratedabove, and rather the invention embraces such modified embodiments thatcome within the scope of the following claims. Further, it is understoodthat in these claims, means plus function clauses are intended to coverthe structures described herein as performing their recited function,and also both structural equivalents and equivalent structures. As anexample, though a nail and a screw may not be structural equivalentsinsofar as a nail employs a cylindrical surface to secure parts togetherwhereas a screw employs a helical surface, in the context of fasteningparts, a nail and a screw are equivalent structures.

What is claimed is:
 1. An air return bulkhead for attachment to a wallhaving a refrigerator mounted thereon, the refrigerator having agenerally horizontally oriented lateral width, the air return bulkheadcomprising: a. a floating panel including opposing front and rear faces,the faces having an upper edge, an opposing lower edge, and opposingside edges between which the width of the floating panel is defined, b.an upper support panel integrally connected to the floating panel at itsupper edge, wherein the upper support panel extends continuously acrossthe width of the floating panel and descends rearwardly from the rearface of the floating panel, c. two side support panels, each sidesupport panel being connected to a respective one of the side edges ofthe floating panel and descending rearwardly from the rear face of thefloating panel, wherein the upper support panel and side support panelsmay be situated adjacent the trailer wall with the floating panel spacedfrom the trailer wall, thereby defining a plenum chamber between thefloating panel, the trailer wall, the upper support panel, and the sidesupport panels, and wherein one or more openings are defined in the airreturn bulkhead beneath the lower edge of the floating panel, theopenings allowing passage of air to the plenum chamber, whereby at leasta portion of the upper support panel may be cut away to define a spacewherein the lateral width of the refrigerator may be fit when thebulkhead is situated against the trailer wall, the refrigerator therebyresting at least partially within the plenum chamber.
 2. The air returnbulkhead of claim 1 wherein the upper support panel has a width of atleast 66 inches.
 3. The air return bulkhead of claim 1 wherein the uppersupport panel includes laterally spaced ridges rising therefrom.
 4. Theair return bulkhead of claim 1 wherein the upper support panel includeslaterally spaced valleys depressed therein.
 5. The air return bulkheadof claim 1 wherein the front face of the floating panel includes alaterally-extending ridge rising therefrom.
 6. The air return bulkheadof claim 1 further comprising two or more support columns resting belowthe lower edge of the floating panel, wherein each support columnincludes a column floor extending downwardly from the lower edge of thefloating panel, and opposing column 5 walls descending rearwardly fromthe column floor.
 7. The air return bulkhead of claim 6 wherein the oneor more openings includes an aperture defined within one of the supportcolumns.
 8. The air return bulkhead of claim 6 further comprising one ormore lower support panels, each of the lower support panels descendingrearwardly from the lower edge of the floating panel between two of thesupport columns.
 9. The air return bulkhead of claim 8 wherein the oneor more openings includes an aperture defined within one of the lowersupport panels.
 10. The air return bulkhead of claim 1 furthercomprising one or more depressions recessed into the front face of thefloating panel between the upper and lower edges of the floating panel.11. The air return bulkhead of claim 10 wherein at least one of thedepressions is spaced from the upper, lower, and side edges of thefloating panel.
 12. The air return bulkhead of claim 10 furthercomprising two or more support columns resting below the lower edge ofthe floating panel, wherein each support column includes opposing columnwalls descending rearwardly with respect to the rear face of thefloating panel, and a column floor situated between the column walls andextending downwardly with respect to the lower edge of the floatingpanel.
 13. The air return bulkhead of claim 12 wherein at least one ofthe depressions is recessed into the front face of the floating paneldirectly above one of the support columns.
 14. The air return bulkheadof claim 12 wherein at least one of the depressions defines a supportflute which includes elongated opposing flute walls extending betweenopposing flute ends.
 15. The air return bulkhead of claim 14 wherein atleast one of the flute ends is recessed into the front face of thefloating panel directly above one of the support columns.
 16. An airreturn bulkhead comprising: a. a floating panel including opposing frontand rear faces, an upper edge, an opposing lower edge, and opposing sideedges, b. an upper support panel descending rearwardly from the rearface of the floating panel at its upper edge, c. two side supportpanels, each side support panel descending rearwardly from the rear faceof the floating panel at one of its side edges, d. one or moredepressions recessed into the front face of the floating panel betweenthe upper and lower edges of the floating panel, e. two or more supportcolumns, wherein each of the support columns includes opposing columnwalls extending downwardly with respect to the lower edge of thefloating panel and descending rearwardly with respect to the rear faceof the floating panel.
 17. The air return bulkhead of claim 16 whereinthe upper support panel is integrally formed with the floating panel andextends continuously across the width of the floating panel.
 18. The airreturn bulkhead of claim 16 wherein the upper support panel includesspaced ridges defined thereon.
 19. The air return bulkhead of claim 16wherein the upper support panel includes spaced valleys defined therein.20. The air return bulkhead of claim 16 wherein at least one of thedepressions is spaced from the upper, lower, and side edges of thefloating panel.
 21. The air return bulkhead of claim 16 wherein one ormore support columns has an aperture defined therein, wherein eachsupport column having the defined aperture includes a passage definedbetween its column walls, with the aperture opening onto the passage.22. The air return bulkhead of claim 16 further comprising one or morelower support panels descending rearwardly from the lower edge of thefloating panel between two of the support columns.
 23. The air returnbulkhead of claim 22 wherein at least one of the lower support panelshas an aperture defined therein.
 24. The air return bulkhead of claim 16wherein at least one of the depressions is recessed into the front faceof the floating panel directly above one of the support columns.
 25. Theair return bulkhead of claim 24 wherein at least one of the depressionsdefines a support flute, each support flute including elongated opposingflute walls extending between opposing flute ends.
 26. The air returnbulkhead of claim 25 wherein at least one of the flute ends is recessedinto the front face of the floating panel directly above one of thesupport columns.
 27. An air return bulkhead for attachment to a wallhaving a refrigerator mounted thereon, the refrigerator having agenerally horizontally oriented lateral width, the air return bulkheadcomprising: a. a floating panel including opposing front and rear faces,an upper edge, an opposing lower edge, and opposing side edges betweenwhich the width of the floating panel is defined, b. an upper supportpanel descending rearwardly from the upper edge of the floating panel,c. two side support panels, each side support panel descendingrearwardly from a respective one of the side edges of the floatingpanel, d. one or more depressions recessed into the front face of thefloating panel between the upper and lower edges of the floating panel,wherein the upper support panel and side support panels may be situatedadjacent the trailer wall with the floating panel spaced from thetrailer wall, thereby defining a plenum chamber between the floatingpanel, the trailer wall, the upper support panel, and the side supportpanels, and wherein one or more openings onto the pleunum chamber aredefined in the air return bulkhead beneath its lower edge, whereby atleast a portion of the upper support panel may be cut away to define aspace wherein the lateral width of the refrigerator may be fit when thebulkhead is situated against the trailer wall, the refrigerator therebyresting at least partially within the plenum chamber.
 28. The air returnbulkhead of claim 27 wherein the upper support panel is integrallyformed with the upper support panel and extends continuously across thewidth of the floating panel.
 29. The air return bulkhead of claim 27wherein the upper support panel includes spaced ridges defined thereon.30. The air return bulkhead of claim 27 wherein the upper support panelincludes spaced valleys defined thereon.
 31. The air return bulkhead ofclaim 27 wherein at least one of the depressions is spaced from theupper, lower, and side edges of the floating panel.
 32. The air returnbulkhead of claim 27 further comprising two or more support columnsresting below the lower edge of the floating panel, wherein each supportcolumn includes a column floor extending downwardly from the lower edgeof the floating panel, and opposing column walls descending rearwardlyfrom the column floor.
 33. The air return bulkhead of claim 32 whereinthe one or more openings includes an aperture defined in one of thesupport columns.
 34. The air return bulkhead of claim 32 furthercomprising a lower support panel descending rearwardly from the loweredge of the floating panel between two of the support columns.
 35. Theair return bulkhead of claim 34 wherein the one or more openingsincludes an aperture defined within one of the lower support panels. 36.The air return bulkhead of claim 32 wherein at least one of thedepressions is recessed into the front face of the floating paneldirectly above one of the support columns.
 37. The air return bulkheadof claim 32 wherein at least one of the depressions defines a supportflute, the support flute including elongated opposing flute wallsextending between opposing flute ends.
 38. The air return bulkhead ofclaim 37 wherein at least one of the flute ends is recessed into thefront face of the floating panel directly above one of the supportcolumns.